Another motor controller

[Brumm]

Many thanks Sebastian, but for my eyes the Uno has the same oval can, to the left side of the red rectangle. My Mega has also this can, stamped 16.000 (MHz?), but to my surprise on the Zero (32bit) I don't see a quartz? Or then it is really small, unfortunately there is no large pic on the Arduino site.

Not that it is really important for me, but I never heard about these resonators. The quartz works also by resonance, afaik.

Greetings, Hansrudolf

[Bonzo]

Just spotted this:
http://www.webrotate360.com/Blog/post/Computorized-DIY-Turntable-For-360-Product-Photography.aspx

It's not a proper turntable but... 

[alexg_ht]

Hi Sebastian,

Can I use a Raspberry Pi to control the Arduino Breadboard version?

Thanks.

[CyberSeb]

Hi Alex,

yes, this could work. I'm not sure if the Chinese Arduinos are supported on a Raspberry Pi (if there is a serial driver availble on the ARM architecture), but I believe it should work!

Sebastian

[alexg_ht]

Hi Alex,

yes, this could work. I'm not sure if the Chinese Arduinos are supported on a Raspberry Pi (if there is a serial driver availble on the ARM architecture), but I believe it should work!

Sebastian

I just ordered a real Arduino.

[alexg_ht]

I did a breadboard verison of Sebastian Mate's controller using a Raspberry Pi and it worked.

Speed regulation is superb, changing from 33-1/3 to 45rpm is a breeze.

Now am waiting for his PCB/DIY kit.

[arched]

Any news!?

I want to buy a MagicQuartz kit!

[OsteSpiser]

Many thanks Sebastian, but for my eyes the Uno has the same oval can, to the left side of the red rectangle. My Mega has also this can, stamped 16.000 (MHz?), but to my surprise on the Zero (32bit) I don't see a quartz? Or then it is really small, unfortunately there is no large pic on the Arduino site.

 It is very small  in a different kind of "tin"

( I cheated and looked at the schematics on the Arduino site )

-kristian

[CyberSeb]

Hi Rasmus,

sorry that you and the others have to wait so long. At the moment, I'm extremely busy with other things (e.g. my PhD thesis, which has to be finished within 6 months -- and I haven't really started writing  )

But I'm honestly spending as much as time possible to get this thing finished.

I've almost finished the final version of the PCB, and I hope that I will be able to order test PCBs this weekend. I've also made huge improvements on the firmware. There are some great new features which had to go into the final version (automatic voltage reduction, "live" speed display where appropriate, remembering and restoring the initial speed at the beginning of the record -- see my webpage for details). I still need to implement the "soft" ramping between the normal and reduced voltages and fix some bugs.

Also keep in mind that I want this thing to be perfect from scratch, as there will be no user-upgradable firmware. Under any circumstances, I want to avoid delivering a product that has bugs. And the firmware is a complex beast, with more than 5000 lines of C code ...

I hope that you understand my situation. But I hope that I will finish it soon - let the next holidays come!  

@Kristian: Thanks for pointing to this! Looks like a real chrystal. I was not aware that the Arduino Zero has one! 

Sebastian

[arched]

Sebastian, I understand of course.  When I read my comment now it comes of rather whiney, I should have put a smiley after it. 

Impressive that you want to sell a perfect bug free product, and I know from own work (fullstack sysadm) that testing every corner case is very difficult (almost impossible) without the users. I applaud your effort and will look forward to your motor controller with patience.

OT (but since you mentioned your thesis): I wrote most of my master thesis (I know, it's nothing compared to a PhD) totally isolated in a run down summerhouse by the north sea, with no Internet, in the course of two weeks. I can wholeheartedly recommend this approach, as a way to minimize procrastination.

[CyberSeb]

Rasmus, thanks a lot for your patience! No, your post does not sound whinier than mine. I'm really also annoyed to put off my interested customers. I really need to finish it soon.   

The firmware is already working very well, but I've noticed some bugs, especially in "uncommon" situations. This needs to be fixed. One challenge is that the firmware is totally user-configurable (there are more than 30 parameters which can be tweaked), and it has to work with different turntables. I need to test various combinations in different operation modes.

The whole thing also has to operate with minimal user interaction - in a safe way. This means that it has to automatically deal with "challenges" (e.g. recognizing that a automatic turntable has shut down). It also has to resume into the last mode of operation when switched off and on again, after standby, and so on. The firmware has become really complex. I want the user to be able to just enjoy music, and not to fiddle around with the MagicQuartz unit.

It will not be totally bug free (you're right, that's impossible), but hopefully close. The initial firmware will probably include ALL features, i.e. there will be no further updates with additional features. I don't want to give the customers any reason to upgrade the firmware because to bugs.

Sebastian

PS: The idea with writing the thesis in isolation sounds great! Thanks for this tip!

[terenceng]

Hi Sebastian,

I thought instead of sending you e-mails, it would better benefit the wider community here if I ask on the forum itself.
Just concerned on the range of turntable motors that will work with the MagicQuartz as i know the output wattage is significantly lesser than Nigel's Speed Controller?

(Of course there would be bound to have some comparisons given the same product being offered)

AFAIK, a friend of mine who have done the NSC, ran it on VPI Classic 1 (a 10watt) motor and according to him and it runs pretty hot. So I am just concerned on the reliability part of MagicQuartz as would it run even hotter on a 15-19 watt lenco motor.

We always see Valhalla (Linn LP12's speed controller) being faulty and I heard that they run really very very hot and you could not even touch it.

Is it possible to enlighten us further (with hopes that it doesn't stall you in your development of MagicQuartz)

Thanks Seb!

Terence.

[mustafa]

Hi,

Having got a Nigel speed controller, it would be very interesting, to see another one out there.  Good luck with your project.

regards

Mustafa

[CyberSeb]

Hi Terence,

thanks for posting this here.

As far as I know the NSC uses a purely analog amplifier design. MagicQuartz is digital and should be much more power efficient, i.e. run cooler.

However, 19 watt is probably on the upper side (I can't say "limit", because I haven't done real measurements for the upper limit). Does a Lenco really consume 19 watt when running? I think this is the upper limit when the turntable is spinning up, and it will drop significantly once it's fully running. Unfortunately, I don't have a Lenco, but I would appreciate it if someone could measure this (with a simple power meter).

From my early tests it is capable of driving my Dual 1219 and Dual 1019 in parallel, which are rated 17 watt (together).

In any case MagicQuartz should be able to provide much more current when using a bigger heatsink and possibly a bigger power supply.

@Mustafa: Thanks!  

Sebastian

[terenceng]

Thanks for the reply and prompt response Seb! Please take your time in developing a bug free version! I am forcing myself to wait patiently 

It seems like there isn't much to worry about then.. As I know, a bigger power supply would just mean a bigger rating for the transformers yes?

Also, my lenco is the 230v version.. How low can I run it till the point it won't strain the motor? (Apologize in advance if this is a stupid question, but am afraid it may not be a good idea to run too low). AFAIK I should run it to the point where i don't compensate too much speed loss by lowering the voltage.. is that right?

I have read somewhere some are operating the 110v version of the lenco successful at 75/80v which yields the best results. That is roughly 3/4 of the designated operating voltage (i.e, 75/110). So is that equivalent to about 155v on a 230v version of the lenco motor? Or I could run it at 75/80v and achieve the same results?

Thanks!